It has two types: type 1 resembles the M734 fuze, and type 2 resembles the M935 fuze. This is accomplished by depressing the barrel until the top of the mask is clear. Upon completion of any bipod movement on the barrel, the gunner ensures that the firing pin recess is facing upward. The components of the mortar consist of a cannon, mount, and baseplate. The sight bracket is attached to the buffer carrier, which is fitted to the traversing screw assembly. The 60mm mortar section is located in the weapons platoon of the rifle company, is armed with three 60mm mortars, and is If it gets wet or dirty, it must be wiped off at once. It was even a tool used by airborne units, and was dropped in parachute bundles during Operations Neptune, Market Garden, and Varsity. If water is not available, the gunner must stand clear of the mortar until the barrel is cool. Cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the U.S. Marine Corps and U.S. Navy only. The M252 81 mm medium weight mortar is a British designed smooth bore, muzzle-loading, high-angle-of-fire weapon used for long-range indirect fire support to light infantry, air assault, and airborne units across the entire front of a battalion zone of influence. 4-11. The assistant gunner attempts to maintain the traversing mechanism on a horizontal plane. He levels all bubbles. They are fuzed with the M524-series, M256-series, or M532. The barrel is then rotated a quarter turn to unlock it from the socket, and it is placed in an area designated by the squad leader. PDF Principles of Fire Support B2c2437 Student Handout (3) Markings on rounds. LARGE DEFLECTION AND ELEVATION CHANGES. He tightens the leg-locking handwheel (ensuring the teeth are correctly meshed) and fastens the securing strap over the arm and around the buffers. It comes preset to function on SQ/IMP, and the selector slot should align with the SQ mark on the ogive. If the barrel is hot, the gunner may then apply water to the outside of the barrel until it is cool. Attached to the right of the screw is the traversing handwheel. (4) The bipod locking latch is locked, securing the barrel clamps. When cartridges have been prepared for firing, but are not used, all powder increments and safety wires are replaced. High angles of approach (near vertical) give the lowest burst heights. In addition to supervising the emplacement, laying, and firing of the mortar, he supervises all other squad activities. The gunner stands to the left side of the mortar where he can manipulate the sight, elevating handwheel, and traversing handwheel. It has a time setting of up to 50 seconds. CANNON, 155MM HOWITZER, M185 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A1 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A1B HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A2 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3 HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A3B HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A4 AND CANNON, 155MM HOWITZER, M284 ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A5, M109A6 AND M109A7 AND CANNON, 155MM HOWITZER, M284A2 CHROME ON HOWITZER, MEDIUM, SELF-PROPELLED, 155MM, M109A6 AND M109A7 AND CANNON, 155MM HOWITZER, M199 ON HOWITZER, MEDIUM, TOWED, 155MM, M198 AND CANNON, 155MM HOWITZER, M776 ON HOWITZER, MEDIUM, TOWED, 155MM, M777, M777A1 AND M777A2 AND CANNON, 155MM HOWITZER, M776 CHROME ON HOWITZER, MEDIUM, TOWED, 155MM, M777A2 FIRING PROJECTILE, HE, M795 PROJECTILE, HE, M795 IM PROJECTILE, HE, M1122 PROJECTILE, IR ILLUMINATING, M1123 PROJECTILE, ILLUMINATING, M1124 INCLUDES FIRING TABLES FOR PROPELLANTS: M119A2 (CHARGE 7R), M203A1 (CHARGE 8S), AND MODULAR ARTILLERY CHARGE SYSTEM (MACS) PROPELLANTS: M231 (CHARGES 1L AND 2L), M232 AND M232A1 (CHARGES 3H, 4H AND 5H) (S&I BY PROP SEE DETAILS, FOOTNOTES) . e. The M362A1 and M362 HE cartridges are of steel forge construction and contain about 2.10 pounds of composition B explosive. M252 81mm Medium Extended Range Mortar - Specifications FT 81-AI-3 Firing Tables Mortar, 81mm: M28A1 and M29 Mortar 81mm Self propelled M125A1 and M125 Carrier, 81mm Mortar Tracked XM755 [US Army.] Illuminating is used for battlefield illumination and signaling. d. Multioption. The first ammunition bearer shakes the barrel to dislodge any remnants from the last round fired, and he lowers the barrel into the rotating socket of the baseplate. It is designed to be fired in the indirect fire mode, cannot be fired handheld, and normally utilizes a FDC. News. (4) Extra increments are removed if the cartridge is to be fired with less than full charge. Designed by Thingsym. Cartridges assembled with the M532 fuze must be fired above charge 0. .50: AP, M2 AND CARTRIDGE, CAL. If he is not within 20 mils, the gunner and assistant gunner must make another large shift before moving on. When the approximate alignment is completed, the gunner signals the assistant gunner to lower the bipod by pushing down on the mortar. The elevation change announced must be less than 90 mils and more than 35 mils. He exposes 1 inch (25 millimeters) of cross-level shaft and folds the handle. The removable increments are fitted onto or around the shaft, depending on their type. (5) Do not leave unused increments unburned in combat operational areas. b. It has four function settings: PRX (proximity) causes the cartridge to explode between 3 and 13 feet above the ground; NSB (near-surface burst) causes the cartridge to explode up to 3 feet above the ground; IM (impact) causes the cartridge to explode on contact; and DLY (delay) incorporates a 0.05-second delay in the fuze train before exploding the cartridge. (3) From this train, extend a starting train that will burn against the wind of single increments laid end to end. Proximity (VT). Types of rounds, classification, and characteristics for the 81-mm mortar, M29A1 (Standard B for the 81-mm mortar, M252). Once set to act as an impact fuze, the mechanism cannot be reset for PROX. M252 81mm Medium Extended Range Mortar - Federation of American Scientists (c) The gunner determines mask and overhead clearance by sighting along the barrel with his eye near the breech plug. The M374 cartridge is fitted with the M90 propelling charge. The sight is laid on two aiming posts (placed out 50 and 100 meters from the mortar) on a referred deflection of 2800 mils and an elevation of 1100 mils. This section contains information on how to prepare the 81-mm mortar, M252, for firing, how to conduct safety checks, and, if a misfire should occur during firing, what actions the crew applies to remove the cartridge from the barrel. As a longstanding partner of armed forces around the globe, Rheinmetall supplies a wide array of mortar systems and ammunition. The M252 81mm medium extended range mortar (see diagram below) is a crew-served, smooth bore, muzzle loaded, high angle of fire weapon system. It uses the M772 mechanical time fuze and weighs about 10.6 pounds. It is set using the bladed end of the M18 fuze wrench. Swifty 3 from scratch; Swifty 3 split-repo setup; Swifty Troubleshooting; Mods. If not, he may still fire at the desired range by selecting a charge zone having a higher elevation. The M252 81mm mortar is a smooth-bore, muzzle-loaded, high-angle-of-fire weapon. d. The ammunition is protected from mud, sand, dirt, and water. PDF Principles of Fire Support B2c0289xq Student Handout How the RCGM works: Target coordinates are programed into the RCGM using a portable GPS setter. The Marines' Trusty Mortar Is Getting a Major Upgrade - Popular Mechanics c. The first ammunition bearer ensures that each cartridge is clean, the safety pin is present, and the ignition cartridge is in good condition. The propellant train (except the training cartridge) consists of an ignition cartridge and propellant charges. Standard A ammunition for the M29A1 mortar is Standard B for the M252 mortar (, Light green Yellow band with red markings. Referring and realigning aiming posts ensure that all mortars are set on the same data. He places the sight case and aiming posts to the left front of the mortar position. He exposes 4 inches (100 millimeters) of elevation shaft and folds the handle. Safety before firing is provided by a safety wire, which must be removed just before firing. To set for delay, the selector slot should be rotated clockwise until it is aligned with the "D" mark on the ogive. b. LHMBC. The M853 and M301A3 illuminating ammunition are described herein. Figure 4-8. He releases the securing strap, loosens the leg-locking handwheel, and lowers the plain leg until the locating catch engages in the recess. The assistant gunner exposes 8 inches (200 millimeters) of elevation shaft, leaving the elevation handwheel unfolded. Official websites use .mil The squad leader indicates the direction of fire when mounting. The gunner levels the elevation bubble by turning the elevation micrometer knob and reading the setting on the elevation scale and elevation micrometer--this setting is the minimum mask clearance. Fuzes are not disassembled. The entire squad stays with the mortar. Notches in the setter engage ribs in the setting ring of the fuze. Indirect Fire Mount, M177, in folded position. 81 mm mortar - Wikipedia The M1 was a derivative of the French mle 27/31 system (itself an improved form of the Stokes Trench Mortar of World War 1 fame) and slightly altered to suit American needs. If the primer is not dented, the round may be used again. (2) The M524-series fuze has two function settings: superquick/impact (SQ/IMP) and delay. The cartridge can be fitted with the M524-series, M526-series, M567, or M532 fuzes. I have included my order history, detailed photos, as well as my personal opinion on International Military Antiques, IMA -USA www.ima-usa.com 81mm Display Mortar that they have for sale. The cartridge is painted light green and has red markings and one narrow yellow band. (2) Burn all dead grass or brush within 30 meters around the burning place. Cartridges assembled with the M524 (A1, A2, A3, or A4) fuze are for use by the US Marine Corps and US Navy only. M252 81mm Medium Mortar a. The table on the right describes the three most common setups. Fired . Correctly applying and performing these duties enables the mortar section to perform as an effective fighting team. At this command, the squad proceeds as follows: a. After the bands are broken and the box opened, the rounds should be removed by allowing them to roll out along the lid of the box (Figure 4-8). Its range and explosive power is greater than the M224, yet it is still light enough to be man . In charge was the platoon commander - normally a lieutenant. The fuze wrench, M18, assembles the fuze to the cartridge, and the bladed tip on the end sets PD-type fuzes. The cannon assembly consists of the barrel that is sealed at the lower end with a removable breech plug, which houses a removable firing pin (Figure 4-3). Mortars are indirect-fire weapon systems. 4-4. The baseplate (Figure 4-5) is of one-piece construction, and supports and aligns the mortar for firing. b. Despite its weight though, the 81mm mortar was an important part of the Table of Organization and Equipment of U.S. Army and U.S. Marine Corps maneuver battalions throughout World War II. SMALL DEFLECTION AND ELEVATION CHANGES. TM - Technical Manuals (Range 9) TM - Technical Manuals (Range 10) TM - Technical Manuals (Range 11-4) TM - Technical Manuals (Range 11-5) . The cartridge is painted light green with black markings and one narrow brown band. If the situation allows for a longer waiting period, the dud can be considered safe for handling after 40 hours. All elements given in the fire command are repeated by the squad. (5) With the exception of a few unused increments (within the same ammunition lot number) as replacements for defective increments, excess powder should be removed from the mortar position. The fuzes may be used for day or night operations. c. The assistant gunner stands to the right of the mortar, facing the barrel and ready to load. An internal clock mechanism provides nine seconds of safe air travel (610 to 2,340 meters along trajectory for charge 0 through 9, respectively). Excess increments should not accumulate near the mortar positions but are removed to a designated place of burning and destroyed. c. The first ammunition bearer checks the barrel and ensures that--. The M751 is fitted with a smoke charge that operates on impact. It can provide all-weather, ground-based, close supporting, accurate, immediately Fuze, PD, for 81mm mortar rounds, Italy, WWII, inert Before the mortar is mounted, the squad must perform premount checks. When set at SQ, the fuze functions on point impact or graze contact. An 81 mm mortar is a medium-weight mortar. The first ammunition bearer puts both hands on the cooling fins under the barrel and slowly lifts the barrel until it is horizontal. M252 81mm Mortars The M252 81mm medium extended range mortar (see diagram below) is a crew-served, smooth bore, muzzle loaded, high angle of fire weapon system. The tabulated data of the 81-mm mortar, M252, are shown in Table 4-1. As soon as the sight data are announced, the gunner places it on the sight. The 81mm mortar is a portable, mobile, medium mortar at the infantry's disposal. Mortar Weapon Systems - USAASC M821/M889 81mm HE Mortar Cartridges - GlobalSecurity.org (2) The M84 fuze is a single-purpose, powder-train, mechanical-time fuze used with the 81-mm M301A1 and M301A2 illuminating cartridges. Washington DC 20310-0107, ADRP - Army Doctrine References Publications, ATTP - Army Tactics, Techniques, and Procedures, FY Publication Status Report (CAC required for access), Publishing Resources (CAC required for access), PC/PCO/FMO/EPCO Directory (CAC required for access), usarmy.pentagon.hqda-apd.mbx.customer-service@army.mil, GUN, MACHINE, CAL. Figure 4-4. (2) Color code. End this starting train with not less than 1 meter of inert material (dry grass, leaves, or newspapers). c. Authorized Cartridges. The first ammunition bearer holds the barrel until the assistant gunner has removed the mount. It uses the M185 propelling charge that consists of eight increments fitted into the spaces between the fins and held by a propellant holder. The mortar also offered the promised increase in range as well, allowing fire teams to engage the enemy at distance. When set at delay, the fuze train causes a 0.05-second delay before functioning. Target terrain, such as ice and dry sand, gives lowest burst heights, whereas water and wet ground give highest burst heights. The gunner unlocks the barrel clamp and rotates the barrel, unlocking the breech plug from the rotating socket of the baseplate. The squad leader notifies the FDC of the minimum mask clearance elevation. PDF 81-mm MORTAR, M252 - GlobalSecurity.org It is constructed from ductile cast iron and contains about 1.5 pounds of cyclonite (RDX)/trinitrotoluene (TNT) composition explosive. The M252 is highly accurate up to ranges of 4500m to 5700m depending on the Additional information is included on an ammunition data card inside each container. During training, the gunner may use the driving stake from the aiming post case. Red phosphorus rounds can be fired from the M29/M29A1 at a reduced charge (maximum charge = charge 2). . b. When a misfire occurs, any member of the squad immediately announces, "Misfire." 81MM M252A1. [Firing and Deflection Conversion Tables] - The Portal to Texas History Army Publishing Directorate - Firing Tables All rounds are colored according to their type. The increments are individually wrapped with waterproof bags that are not removed. The M734 multioption fuze is the only one used with the 81-mm mortar. (1) The rotating socket is free to move in a complete circle. The squad leader stands behind the mortar where he can command and control his squad. The M853 cartridge (M252 only) has a cylindrical body that contains an illuminating candle and parachute assembly. REFER DEFLECTION TWO EIGHT SEVEN FIVE (2875), REALIGN AIMING POSTS. He may assist the gunner in shifting the mortar when the gunner is making large deflection changes. Share sensitive information only on official, secure websites. In addition to loading, he swabs the bore after 10 rounds have been fired or after each fire mission.

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